The Hamann Thunder was featured in Bimmer magazine which was a 325i or 328i totally reuilt with M3 everything and a 550hp V10. They only had 0-60mph which was 4.3 or 4.2 I believe and then went on to say that traction, weight and aerodynamic drag were the limiting factors.

That car did have 305s on the rear.

I'm wondering how much of an improvement a supercharger kit will be? I supercharged my 330Ci and that was a huge difference. I'd hate to spend $10k+ on a marginal improvement. I'm sure it would help rocketing out of tight corners on the track but what is the use if you can't put the power to the ground?

DISCLAIMER: I just read this...really not an expert on this.

This is more of an issue of too much torque. The V10 also makes the car much more front heavy and affects rear wheel traction. Also affects the carīs balance. Now this V10 must be a hell of a best after 100kph etc...

Anyway, if you keep the engine NA with a stoker kit, you actually do avoid all these issues as the front of the car is made a tad lighter but you get all that additional power and retain the absolutely great thottle response. FI will undoubtedly add weight albeit perhaps at a lower cost. Although I really doubt anyone will come up with an under 10K FI kit for these cars.